Charmonium spectrum at finite temperature from a Bayesian analysis of QCD sum rules

Philipp Gubler^1a, Kenji Morita² and Makoto Oka¹

¹ Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
² Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan

^a e-mail: phil@th.phys.titech.ac.jp

Published online: 10 February 2012

Abstract

Making use of a recently developed method of analyzing QCD sum rules, we investigate charmonium spectral functions at finite temperature. This method employs the Maximum Entropy Method, which makes it possible to directly obtain the spectral function from the sum rules, without having to introduce any strong assumption about its functional form. Finite temperature effects are incorporated into the sum rules by the change of the various gluonic condensates that appear in the operator product expansion. These changes depend on the energy density and pressure at finite temperature, which are extracted from lattice QCD. As a result, J/ψ and η_c dissolve into the continuum already at temperatures around 1.0 ~ 1.1 T_c.